The overall objective of our research is to define the steps involved in the expression of mammalian genes and to determine how their expression is regulated. Our approach to this problem is to define the initial transcript of a specific gene, namely the one for globin. To this end, we have prepared a globin cDNA cellulose column which selectively retains globin mRNA sequences, and used it to isolate RNAs containing globin mRNA sequences. We have isolated a 16S RNA. During the next granting period we plan to prove that this RNA contains globin mRNA sequences by following its kinetics of hybridization to excess unlabeled globin cDNA and to show that it is kinetically related to mature globin mRNA by performing pulse chase experiments. In addition, we will determine the location of the globin mRNA sequences within the 16S RNA precursor using the partial alkali degradation method. BIBLIOGRAPHIC REFERENCES: Purification of a Putative Precursor of Globin Messenger RNA from Mouse Nucleated Erythroid Cells, S.P. Kwan, T.G. Wood and J.B. Lingrel, Proc. Natl. Acad. Sci. USA (1977) 74, 178-182. Purification of Biologically Active Globin mRNA using cDNA-Cellulose Affinity Chromatography, T.G. Wood and J.B. Lingrel, J. Biol. Chem. (1977) 252, 457-463.